This invention relates to blood perfusion pumps. A coupler for connecting a kinetic pump to a perfusion control console is described.
Blood is a fragile material which must be handled carefully. Early efforts at pumping blood in support of surgical procedures involved the use of the peristaltic or roller pump. This type of pump is easy to manufacture from biocompatible materials. This type of pump is also easy to control with simple motor controllers. However, these and other positive displacement pumps are inadequate when used to support some surgical procedures. The principal drawbacks of such pumps are the generation of air emboli, the disruption of tubing connectors and the fracture of pump tubing.
In response to these defects in the prior art, a new type of pump was introduced. U.S. Pat. No. 3,617,324 to Rafferty, E. et al. describes this new type of rotary pump. This type of pump has no vanes or impellers and is now commonly called a kinetic pump. The kinetic pump provides a smooth surface rotator which moves blood from a central inlet to the periphery of a pump housing. Although the angular velocity of the blood within the pump is essentially constant, the linear velocity continues to increase as the radial distance from the inlet increases. To preserve the flow pattern through the pump, the rotators converge so that rotator passages remain constant in cross sectional area. The spacing between the rotator passages varies as an inverse function of the radial distance from the rotator axis. This geometry of the kinetic pump results in the principal benefits of such pumps which are the prevention of cavitation, and the prevention of over pressurization of the blood.
The earliest versions of these pumps were powered by internal motor structures as shown in U.S. Pat. No. 4,037,984 to Rafferty, E. et al. An alterative to the internal motor is taught by U.S. Pat. No. 3,864,055 to Kletschka, which shows a drive shaft protruding from the pump housing.
The problems presented by each of these prior art approaches were overcome by the adoption of the driver apparatus shown in FIGS. 1,2 and 3. Briefly, the pump is a disposable item which is discarded after a single use. As such, the pump is supplied as a sterilized and sealed unit. The pump is driven by the magnetic coupling of rotating drive magnets located in the control console and driven magnets embedded in the pump rotator.
Although the kinetic pump in its various forms has been successful in a wide variety of clinical settings, sophisticated control apparatus is required to monitor and supervise its operation. Currently, the control apparatus is supplied in a console which houses the drive motor and the supervisory electronics. The modern console may further include RPM monitor and control apparatus, along with pressure and flow monitoring apparatus.
The pump is mounted directly on the console in view of the physician or remotely from the drive console at or near the patient. By locating the pump close to the patient the amount of tubing required to hook the kinetic pump into the patients vascular system is reduced. In either location, the pump is driven magnetically. Typically the pump is placed into a pump receiver located on either, the console or on a remote driver unit.
Each manufacturer has a specialized pump design which renders certain combinations of pumps and consoles incompatible. This strategy prevents the use of incompatible systems and therefore provides additional protection to the patients.